Tracking Traitors in Web Services via Blind Signatures

This paper presents a method and its implementation, built on the blind signatures protocol, to trace users sharing their licenses illegally when accessing services provided through Internet (Web services, Streaming, etc). The method devised is able to identify the legitimate user from those users who are illegally accessing services with a shared key. This method is robust when detecting licenses built with no authorization. An enhancement of the protocol to identify the last usage of a certain license is also provided, allowing to detect a traitor when an unauthorized copy of a license is used

Review and Comparison of Intelligent Optimization Modelling Techniques for Energy Forecasting and Condition-Based Maintenance in PV Plants

Within the field of soft computing, intelligent optimization modelling techniques include various major techniques in artificial intelligence. These techniques pretend to generate new business knowledge transforming sets of "raw data" into business value. One of the principal applications of these techniques is related to the design of predictive analytics for the improvement of advanced CBM (condition-based maintenance) strategies and energy production forecasting. These advanced techniques can be used to transform control system data, operational data and maintenance event data to failure diagnostic and prognostic knowledge and, ultimately, to derive expected energy generation. One of the systems where these techniques can be applied with massive potential impact are the legacy monitoring systems existing in solar PV energy generation plants. These systems produce a great amount of data over time, while at the same time they demand an important e ort in order to increase their performance through the use of more accurate predictive analytics to reduce production losses having a direct impact on ROI. How to choose the most suitable techniques to apply is one of the problems to address. This paper presents a review and a comparative analysis of six intelligent optimization modelling techniques, which have been applied on a PV plant case study, using the energy production forecast as the decision variable. The methodology proposed not only pretends to elicit the most accurate solution but also validates the results, in comparison with the di erent outputs for the di erent techniques

Perspectivas de la experimentación animal en ciencias biomédicas

En la presente revisión bibliográfica se pretende realizar un ejercicio de divulgación científica de un tema tan controvertido como es la experimentación con animales en los últi¬mos siglos, los orígenes, sujetos y objetivos de esta práctica, el estado actual tanto ético como legislativo y lo que nos cabe esperar de la misma en los años venideros. Una visión verificada con un importante componente social de hacia dónde se dirigen este tipo de ensayos, los retos, el futuro que nos cabe esperar y las perspectivas que del mismo se derivan en relación al ejercicio de la actividad.In the present literature review intends to carry out an exercise of scientific disclosure of such a controversial topic as is the experimentation with animals in the past few centuries, the mos signal sources, subjects and objectives of this practice, the current state both ethical as legislative and what we can expect from the same in the coming years. A vision verified with an important social component of where they are headed this type of testing, the challenges, the future that we can expect and the prospects arising from it in relation to the exercise of the activity

Subjective quality assessment in stereoscopic video based on analyzing parallax and disparity

Disparity may cause visual discomfort. Pairs of video sequences with different levels of parallax, both negative and positive, were presented together to the observers. The observers evaluated the cases in which visual discomfort occurred after visualizing the transition on each pair

Proposal for Characterization of 3DTV Video Sequences Describing Parallax Information

Recommendations such as P.910 suggests parameters TI (temporal information) and SI (spatial information) for characterizing video sequences for quality assessment. In this paper, we suggest two additional parameter based on disparity called SPI (spatial parallax information) and TPI (temporal parallax information) to characterize 3DTV video sequences for this purpose

Insertion of impairments in test video sequences for quality assessment based on psychovisual characteristics

Assessing video quality is a complex task. While most pixel-based metrics do not present enough correlation between objective and subjective results, algorithms need to correspond to human perception when analyzing quality in a video sequence. For analyzing the perceived quality derived from concrete video artifacts in determined region of interest we present a novel methodology for generating test sequences which allow the analysis of impact of each individual distortion. Through results obtained after subjective assessment it is possible to create psychovisual models based on weighting pixels belonging to different regions of interest distributed by color, position, motion or content. Interesting results are obtained in subjective assessment which demonstrates the necessity of new metrics adapted to human visual system

Definition of masks related to psychovisual features for video quality assessment

Video Quality Assessment needs to correspond to human perception. Pixel-based metrics (PSNR or MSE) fail in many circumstances for not taking into account the spatio-temporal property of human's visual perception. In this paper we propose a new pixel-weighted method to improve video quality metrics for artifacts evaluation. The method applies a psychovisual model based on motion, level of detail, pixel location and the appearance of human faces, which approximate the quality to the human eye's response. Subjective tests were developed to adjust the psychovisual model for demonstrating the noticeable improvement of an algorithm when weighting the pixels according to the factors analyzed instead of treating them equally. The analysis developed demonstrates the necessity of models adapted to the specific visualization of contents and the model presents an advance in quality to be applied over sequences when a determined artifact is analyzed

Simulation-based optimization of cycle timing for CO2 capture and hydrogenation with dual function catalyst

[EN] CO2 methanation could play a significant role in the future energy system. The excess of renewable electric energy can be transformed into storable methane to balance the energy demand when required. Moreover, the CO2 methanation can be performed alternating steps of CO2 storage and reduction, avoiding expensive CO2 purification steps. In this work, we will use a previously developed and validated model to optimize by simulation the CO2 adsorption and hydrogenation cycles timing (t(CO2)/t(H2)). The performance of the catalyst is quantified by the CO2 conversion (X-CO2, %), H-2 conversion (X-H2, %) and CH4 production (Y-CH4, mmol g(-1) cycle(-1)). Long adsorption and hydrogenation times result in high CH4 productions per cycle, however, low CO2 and H-2 conversion. Therefore, adsorption times close to the catalyst saturation (t(CO2)=60 s) and moderate hydrogenation times are preferable. To better select the optimal hydrogenation time, a new catalytic parameter is set, the average formation rate of CH4 (rCH(4), mu mol g(-1) s(-1)). The optimal hydrogenation time is set at 120 s. In addition to having a high average formation rate of CH4, t(CO2)/t(H2)= 60/120 cycle timing would allow to work with three identical beds in parallel, one in adsorption mode and two in regenerating mode. With the optimum cycle timing of 60/120 the production of CH4 results in 148 mu mol g(-1) cycle(-1) (1.2 mu mol CH4 g(-1) s(-1)) and a CO2 and H-2 conversion of 25% and 43%, respectivelyThe financial support from the Economy and Competitiveness Spanish Ministry (CTQ2015-67597-C2-1-R and PID2019-105960RB-C21) and the Basque Government (IT1297-19) is acknowledged. The authors thank for technical and human support provided by SGIker (UPV/EHU Advanced Research Facilities/ ERDF, EU). One of the authors (ABL) also acknowledges the Economy and Competitiveness Spanish Ministry for his PhD grant (BES-2016-077855)

Condition assessment of water infrastructures: application to Segura river basin (Spain)

The paper deals with the condition assessment of water management infrastructures such as storage facilities, water mains and water distribution facilities. The objective is to develop a methodology able to provide a fast, simple assessment of present asset condition, that can also be used for predicting future conditions under different investment scenarios. The authors investigate the use of different methodologies to assess condition with focus on simple, indirect condition indices based on maintenance records, such as Infrastructure Value Index (IVI) and Asset Sustainability Index (ASI). The novelty of the approach presented is the development of a methodology that combines an asset inventory together with maintenance data, that can be integrated hierarchically, delivering an assessment of condition of elements, assets and groups of assets in a bottom-up fashion. The methodology has been applied to a group of water management infrastructures of the Segura River Basin in Spain. The main conclusion is that the proposed methodology allows to assess assets' sustainability based upon past and current trends in operation and maintenance budgets, providing a baseline for planning future maintenance actions.This research received no external funding

Thermographic studies of cocurrent and mixed flow spray drying of heat sensitive bioactive compounds

Production of powders of heat sensitive bioactive compounds in a bench scale spray drier was studied under cocurrent and mixed flow pattern conditions using two inlet air temperatures of 200 and 120 °C. Two natural colorants (riboflavin-5-phosphate and red beet) and an enzyme (alpha-amylase), were selected for experimentation. Thermographic studies showed interesting asymmetric profiles of temperatures outside and inside of the drying chamber, because turbulent air flow conditions and thermal trajectories of atomized drops during its drying process were dependent on flow patterns. Powders of natural colorants maintained its color strength, and alpha-amylase powders retain more than 82.9% of its enzyme activity even at the highest air temperature of 200 °C and using mixed flow. This work concludes that spray drying under cocurrent and mixed-flow patterns of heat labile bioactive compounds is feasible, influencing drying yields and the properties of powders obtained